The present invention relates generally to monitoring and reporting systems using cellular carriers.
Various forms of monitoring and reporting systems are often associated with vending machines. Such systems can provide periodic monitoring and reporting of various occurrences within the machines, such as inventory changes, maintenance requirements, service calls, cash receipts, demand for specific products, sold-out conditions, and various alarm conditions, among others.
Some monitoring and reporting systems include a central computer complex which receives data from multiple vending machines at remote locations. In such systems, a communication link is established between the central computer and the individual machines through the use, for example, of standard telephone lines or radio communications. At predetermined intervals, each vending machine accesses the communication link and calls the central computer. Once communication is established, the vending machine can transmit pertinent information about its status. Such systems can help eliminate unnecessary service calls and facilitate better supply route planning. The monitoring and reporting systems can lead to improved auditing practices as well as increased sales.
The use of cellular communication systems has become increasingly popular for general telecommunications because such systems offer several advantages over land-based telephone lines and other radio links. It is desirable to extend the use of such communication systems to vending machine monitoring and reporting systems.
Currently, however, various cellular carriers exist for cellular data communication systems. Such carriers include, for example, RAM Mobitex, ARDIS/DATA-TAC, Cellular Digital Packet Data ("CDPD"), and Circuit Switched Cellular ("CSC"). Each of those systems operates using its own protocol as well as different frequencies or frequency ranges for transmitting and receiving signals. Thus, for example, CDPD and CSC operate with a transmit frequency in the range of 824-849 megahertz ("MHz") and a receive frequency in the range of 869-894 MHz. RAM Mobitex, on the other hand, uses a transmit frequency in the range of 896-902 MHz and a receive frequency in the range of 935-941 MHz; ARDIS/DATA-TAC uses a transmit frequency in the range of 806-849 MHz and a receive frequency in the range of 851-869 MHz.
Based on actual or perceived advantages or disadvantages of one cellular carrier with respect to other cellular carriers, owners or operators of vending machine networks may wish to select a particular cellular carrier to support the vending machine monitoring and reporting system. However, each vending machine in the system must be designed with a telemetry device capable of transmitting and receiving information using the specified frequency ranges according to the particular cellular carrier protocol. This requirement is further complicated because the machines in the vending machine monitoring and reporting system may differ from one another. It is, therefore, desirable to provide a standard vending machine telemeter device which can be adapted for use with any one of multiple cellular carriers and which can be incorporated easily into vending machines of different types.